Subsea Processing System to go Online this year in Brazil

The Marlim Field in the Campos Basin is the host for the world´s first operational system for deepwater subsea separation of heavy oil and water including the vital water reinjection to boost production in this mature Brazilian oil field and may be a key factor in expanding the production life of other mature fields in Brazil.

Marlim is located in the north-eastern part of the Campos Basin, about 110km offshore of Rio de Janeiro, in water depths ranging from 650m to 2,600m (2,100 to 8,500ft). It has some 102 production wells, 50 injection well and 8 floating production units (FPU), devoted to the extraction of O&G. Marlim as a mature field approaching 20 years in operation, is producing an increasing amount of water, which is limiting the oil handling capacity of the surface facilities, and sand, which has the potential for damaging the overall system. The pressure from the well is also decreasing, necessitating a water injection system to increase the output efficiency of the wells.

Over 80km of rigid pipelines and 400km of flexible lines have been laid on the field. The field produces around 390,000 bopd and 252,000 bpd of water, and around 705,000 bwpd are injected into the field.

FMC Technologies was awarded a $90 million contract by Petrobras in 2009, to supply a custom subsea separation system for the Marlim Field. The subsea separation module separates the heavy oil (20º API), natural gas, sand and water at a depth of 900m (2,950ft). The separation system includes cyclone modules that will perform water treatment prior to re-injecting the water back into the reservoir and the system also applies FMC´s proprietary pipe separator design, developed along with Statoil. It will also be the first sparation system to include subsea re-injection of water into the reservoir to boost production. It will also include a vertical connection system and will be capable of operating at pressures of up to 5,000p.s.i and temperatures up to 80 ºC (176 ºF). The system is being jointly engineered between FMC’s operations in Brazil, Norway and the Netherlands and the manufacturing, integration and testing procedures will be performed at the company’s Rio de Janeiro facility, with deliveries projected to begin in 2011 for operations to begin this same year.

The subsea separation, pumping and water re-injection system, developed by Petrobras and FMC, will be installed at a water depth of 2,950 feet (900 meters) and answers the challenges of maturing fields. The system will receive the production stream, which contains a mixture of oil, gas, water and sand, and will first separate the gas from the liquids. Then, the heavy oil will be separated from the water, using the novel pipe separation design that was licensed and developed by FMC along with Statoil.

The contract for the subsea separation system also includes topside and subsea controls, tooling and skids, a water injection pump system, a full technology and qualification program for validation of the subsea and processing equipment, system integration testing, offshore commissioning and technical assistance for installation.

It is hoped that once the system is fully tested and goes operational not only increase the efficiency of the Marlim Field production but also raise the profit margin for the mature field. A similar subsea separation system may also be eventually used on other mature fields in the Campos Basin and also may be an alternative for pre-salt in the Campos Basin and deepwater pre-salt plays in the Santos and Espirito Santo Basins.

Claudio Paschoa